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Negative active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same

a rechargeable lithium battery and negative active material technology, applied in the direction of cell components, final product manufacturing, sustainable manufacturing/processing, etc., can solve the problems of deterioration of the cycle characteristics of the rechargeable lithium battery, the element itself has not yet been commercialized as negative active material, etc., to improve the cycle-life characteristics and initial efficiency

Inactive Publication Date: 2007-05-03
SAMSUNG SDI CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0012] One embodiment of the present invention provides a negative active material for a rechargeable lithium battery having improved cycle-life characteristics and initial efficiency.

Problems solved by technology

However, elements themselves have not yet been commercialized as negative active materials because the elements (such as Si, Sn, Al, and so on) form alloys with lithium during charge-discharge and undergo volume expansion and shrinkage resulting in element pulverization.
As a result, the cycle-life of the battery may decrease.
Thereby, as the silicon compound has low electro-conductivity, the silicon compound is insufficiently utilized for negative active materials and the cycle characteristics of the rechargeable lithium battery are deteriorated.
Thereby, the linkage of the silane coupling agent is broken to release the silicon compound from the graphite such that the silicon compound is insufficiently utilized as a negative active material.
As a result, the cycle characteristics of the rechargeable lithium battery are deteriorated.
Further, the silane coupling agent may not be uniformly treated upon preparing the negative electrode material so that it is difficult to provide a negative electrode material having consistent quality.
Further, the material in which a metal such as Si is bound with or coated on the graphite-based carbonaceous material has the same problems.
Thereby, the metal is separated and thus is not sufficiently utilized as a negative active material.
As a result, cycle-life characteristics of the lithium rechargeable battery are deteriorated.

Method used

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  • Negative active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same
  • Negative active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same
  • Negative active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0065] 11.0785 g of maleic acid and 15.3222 g of cobalt acetate (Co(CH3COO)2) were added to 600 ml of distilled water to prepare a precursor solution. Then, 15 g of Si powder having an average particle diameter of less than 44 μm was added to the precursor solution, and NH4OH was added thereto to regulate the pH to 6.5. The resulting mixture was stirred at 80° C. for 30 minutes. The mixture was dried at 130° C. for 24 hours under a vacuum atmosphere, and then heat-treated at 800° C. for 12 hours under a nitrogen atmosphere, thereby preparing a Si negative active material coated with Co and CO3O4.

[0066] In addition, polyvinylidene fluoride was dissolved in N-methylpyrrolidone as a solvent to prepare a binder solution. Super P carbon and the Si negative active material coated with Co and CO3O4 were added to the binder solution, preparing a negative active material slurry. The prepared negative active material slurry was coated on copper foil, and then dried at 130° C. in a vacuum ove...

example 2

[0068] A rechargeable lithium battery was fabricated as in Example 1, except that NH4OH was added to the precursor solution to regulate the pH to 5.2.

example 3

[0069] A rechargeable lithium battery was fabricated as in Example 1, except that NH4OH was added to the precursor solution to regulate the pH to 6.0.

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Abstract

A negative active material for a lithium rechargeable battery is provided. The negative active material includes an active metal core and a crack inhibiting layer disposed on a surface of the active metal core. The crack inhibiting layer includes a metal oxide.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2005-0104200 filed in the Korean Intellectual Property Office on Nov. 2, 2005, the entire content of which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a negative active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same. More particularly, the present invention relates to a negative active material capable of improving the cycle-life characteristics and initial efficiency of high-capacity rechargeable lithium batteries. [0004] 2. Description of the Related Art [0005] The use of portable electronic instruments is increasing as electronic equipment gets smaller and lighter due to developments in high-tech electronic industries. Therefore, studies of high-capacity negative active mat...

Claims

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Application Information

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IPC IPC(8): H01M4/58H01M4/62B05D5/12H01M4/02H01M4/134H01M4/139H01M4/1395H01M4/50H01M4/505H01M4/52H01M4/525H01M10/0569H01M10/058
CPCH01M4/134H01M4/139H01M4/1395H01M4/366H01M4/505H01M4/525H01M10/0569H01M10/058H01M2004/021H01M2004/027Y02E60/122Y02E60/10Y02P70/50H01M4/02H01M4/38
Inventor KANG, YONG-MOOKKIM, JOON-SUPLEE, SANG-MINKIM, SUNG-SOO
Owner SAMSUNG SDI CO LTD